Traditional radio frequency (RF) amplifiers boost low-power analog input signals to a higher power level. The outputs of traditional RF amplifiers manufactured with similar operating characteristics can be electrically combined to provide greater power output. The ability to configure such RF amplifiers in parallel can provide increased reliability through redundancy, while also offering greater flexibility by enabling different power levels to be provided by parallel amplifier configurations having different numbers of instances of a single basic amplifier design.
FIG. 1 shows a high-level block diagram of a prior-art amplifier system 100, in which two traditional RF amplifiers 106 and 108 are configured in parallel to produce a higher collective power output. An RF input signal from RF source 102 is divided equally by 1:2 splitter 104, where the split signals are fed through equal cable lengths to amplifier 106 and amplifier 108, respectively. The output signals from amplifier 106 and amplifier 108 are then fed through equal-length cables to 2:1 combiner 110 to generate the system's amplified RF output signal.
For RF amplifiers designed to have the same group delay, insertion phase, and gain, as long as the delay caused by the associated cable lengths are equal, the outputs can be near losslessly combined to produce a composite RF output signal.